add examples/network/chargen.c

examples/network/chargen.c

+#include <rtthread.h>
+#include <sys/socket.h> 
+#include <sys/select.h>
+#include <dfs_posix.h> 
+#include "netdb.h"
+
+#define MAX_SERV                 32         /* Maximum number of chargen services. Don't need too many */
+#define CHARGEN_THREAD_NAME      "chargen"
+#if RT_THREAD_PRIORITY_MAX == 32
+#define CHARGEN_PRIORITY         20        /* Really low priority */
+#else
+#define CHARGEN_PRIORITY         200       /* Really low priority */
+#endif
+#define CHARGEN_THREAD_STACKSIZE 1024
+struct charcb
+{
+    struct charcb *next;
+    int socket;
+    struct sockaddr_in cliaddr;
+    socklen_t clilen;
+    char nextchar;
+};
+
+static struct charcb *charcb_list = 0;
+static int do_read(struct charcb *p_charcb);
+static void close_chargen(struct charcb *p_charcb);
+extern int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout);
+
+/**************************************************************
+ * void chargen_thread(void *arg)
+ *
+ * chargen task. This server will wait for connections on well
+ * known TCP port number: 19. For every connection, the server will
+ * write as much data as possible to the tcp port.
+ **************************************************************/
+static void chargen_thread(void *arg)
+{
+    int listenfd;
+    struct sockaddr_in chargen_saddr;
+    fd_set readset;
+    fd_set writeset;
+    int i, maxfdp1;
+    struct charcb *p_charcb;
+
+    /* First acquire our socket for listening for connections */
+    listenfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+    LWIP_ASSERT("chargen_thread(): Socket create failed.", listenfd >= 0);
+    memset(&chargen_saddr, 0, sizeof(chargen_saddr));
+    chargen_saddr.sin_family = AF_INET;
+    chargen_saddr.sin_addr.s_addr = htonl(INADDR_ANY);
+    chargen_saddr.sin_port = htons(19);     // Chargen server port
+
+    if (bind(listenfd, (struct sockaddr *) &chargen_saddr, sizeof(chargen_saddr)) == -1)
+        LWIP_ASSERT("chargen_thread(): Socket bind failed.", 0);
+	
+    /* Put socket into listening mode */
+    if (listen(listenfd, MAX_SERV) == -1)
+        LWIP_ASSERT("chargen_thread(): Listen failed.", 0);
+	
+
+    /* Wait forever for network input: This could be connections or data */
+    for (;;)
+    {
+        maxfdp1 = listenfd+1;
+
+        /* Determine what sockets need to be in readset */
+        FD_ZERO(&readset);
+        FD_ZERO(&writeset);
+        FD_SET(listenfd, &readset);
+        for (p_charcb = charcb_list; p_charcb; p_charcb = p_charcb->next)
+        {
+            if (maxfdp1 < p_charcb->socket + 1)
+                maxfdp1 = p_charcb->socket + 1;
+            FD_SET(p_charcb->socket, &readset);
+            FD_SET(p_charcb->socket, &writeset);
+        }
+
+        /* Wait for data or a new connection */
+        i = select(maxfdp1, &readset, &writeset, 0, 0);
+
+          if (i == 0) continue;
+
+        /* At least one descriptor is ready */
+        if (FD_ISSET(listenfd, &readset))
+        {
+            /* We have a new connection request!!! */
+            /* Lets create a new control block */
+            p_charcb = (struct charcb *)rt_calloc(1, sizeof(struct charcb));
+            if (p_charcb)
+            {
+                p_charcb->socket = accept(listenfd,
+                                        (struct sockaddr *) &p_charcb->cliaddr,
+                                        &p_charcb->clilen);
+                if (p_charcb->socket < 0)
+                    rt_free(p_charcb);
+                else
+                {
+                    /* Keep this tecb in our list */
+                    p_charcb->next = charcb_list;
+                    charcb_list = p_charcb;
+                    p_charcb->nextchar = 0x21;
+                }
+            }
+			else
+			{
+                /* No memory to accept connection. Just accept and then close */
+                int sock;
+                struct sockaddr cliaddr;
+                socklen_t clilen;
+
+                sock = accept(listenfd, &cliaddr, &clilen);
+                if (sock >= 0)
+                    closesocket(sock);
+            }
+        }
+        /* Go through list of connected clients and process data */
+        for (p_charcb = charcb_list; p_charcb; p_charcb = p_charcb->next)
+        {
+            if (FD_ISSET(p_charcb->socket, &readset))
+            {
+                /* This socket is ready for reading. This could be because someone typed
+                 * some characters or it could be because the socket is now closed. Try reading
+                 * some data to see. */
+                if (do_read(p_charcb) < 0)
+                    break;
+            }
+            if (FD_ISSET(p_charcb->socket, &writeset))
+            {
+                char line[80];
+                char setchar = p_charcb->nextchar;
+
+                for( i = 0; i < 59; i++)
+                {
+                    line[i] = setchar;
+                    if (++setchar == 0x7f)
+                        setchar = 0x21;
+                }
+                line[i] = 0;
+                strcat(line, "\n\r");
+                if (write(p_charcb->socket, line, strlen(line)) < 0)
+                {
+                    close_chargen(p_charcb);
+                    break;
+                }
+                if (++p_charcb->nextchar == 0x7f)
+                    p_charcb->nextchar = 0x21;
+            }
+        }
+    }
+}
+
+/**************************************************************
+ * void close_chargen(struct charcb *p_charcb)
+ *
+ * Close the socket and remove this charcb from the list.
+ **************************************************************/
+static void close_chargen(struct charcb *p_charcb)
+{
+    struct charcb *p_search_charcb;
+
+    /* Either an error or tcp connection closed on other
+     * end. Close here */
+    closesocket(p_charcb->socket);
+
+    /* Free charcb */
+    if (charcb_list == p_charcb)
+        charcb_list = p_charcb->next;
+    else
+        for (p_search_charcb = charcb_list; p_search_charcb; p_search_charcb = p_search_charcb->next)
+        {
+            if (p_search_charcb->next == p_charcb)
+            {
+                p_search_charcb->next = p_charcb->next;
+                break;
+            }
+        }
+
+    rt_free(p_charcb);
+}
+
+/**************************************************************
+ * void do_read(struct charcb *p_charcb)
+ *
+ * Socket definitely is ready for reading. Read a buffer from the socket and
+ * discard the data.  If no data is read, then the socket is closed and the
+ * charcb is removed from the list and freed.
+ **************************************************************/
+static int do_read(struct charcb *p_charcb)
+{
+    char buffer[80];
+    int readcount;
+
+    /* Read some data */
+    readcount = read(p_charcb->socket, &buffer, 80);
+    if (readcount <= 0)
+    {
+        close_chargen(p_charcb);
+        return -1;
+    }
+    return 0;
+}
+
+void chargen_init(void)
+{
+	rt_thread_t chargen;
+
+	chargen = rt_thread_create(CHARGEN_THREAD_NAME,
+		chargen_thread, RT_NULL,
+		CHARGEN_THREAD_STACKSIZE,
+		CHARGEN_PRIORITY, 5);
+	if (chargen != RT_NULL) rt_thread_startup(chargen);
+}
+#ifdef RT_USING_FINSH
+#include <finsh.h>
+void chargen()
+{
+	chargen_init();
+}
+FINSH_FUNCTION_EXPORT(chargen, start chargen server);
+#endif